I built my milling machine with help of my friends from industrial waste (it has been updated a lot) over two decades ago and it has moved many times. Last ten years it has been sitting in the corner of my garage.

I'll attach some pictures of making MDF-mold. First i mill mold close to the true dimensions and impregnate it with epoxy resin.
After curing i mill the mold to the final dimensions and paint it with two component acrylic car paint.
Mold after last milling phase

Painted and used one time

Part from mold


I have done all parts using only carbon, and i know that it is not the way to go, if you want the best surface finish. Thin glass layer would help with that, but on the other hand, my prototype is not beauty queen either.
Carbon likes to suck all the resin there is, leaving voids between fiber and mold. But having an extra fiber layer is not only extra weight, but also very annoying to work with. I'm just happy, if i don't have to make "perfect" paint job look crappy afterwards